gpio/pinctrl: sunxi: stop poking around in private vars

This kind of hacks disturbs the refactoring of the gpiolib.

The descriptor table belongs to the gpiolib, if we want to know
something about something in it, use or define the proper accessor
functions. Let's add this gpiochip_lins_is_irq() to do what the
sunxi driver is trying at so we can privatize the descriptors
properly.

Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index f3fcd41..ff8d55a 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1857,6 +1857,15 @@
 }
 EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);
 
+bool gpiochip_line_is_irq(struct gpio_chip *chip, unsigned int offset)
+{
+	if (offset >= chip->ngpio)
+		return false;
+
+	return test_bit(FLAG_USED_AS_IRQ, &chip->gpiodev->descs[offset].flags);
+}
+EXPORT_SYMBOL_GPL(gpiochip_line_is_irq);
+
 /**
  * gpiod_get_raw_value_cansleep() - return a gpio's raw value
  * @desc: gpio whose value will be returned